Mobile communication services are becoming increasingly popular. Hence, there is increasing competition between different mobile operators for building their roaming revenues. Mobile subscribers who frequently roam between two or more countries/networks contribute a majority of this roaming revenue. These mobile subscribers roam between their Home Public Mobile Network (HPMN) and one or more Visited Public Mobile Networks (VPMNs). The HPMN and the VPMNs can be in the same country or may be present in different countries. A local MSISDN of each of the VPMNs (i.e. VPMN MSISDNs) allows the roaming subscribers to call local subscribers of the VPMNs at cheaper local rates instead of expensive roaming rates. In addition, other local subscribers of the VPMN can also call these roaming subscribers of the HPMN at the local rates.
Usually, a roaming subscriber of the HPMN buys a new Subscriber Identity Module (SIM) of each VPMN he wants to visit. Hence, in such a case, the roaming subscriber needs to swap his HPMN SIM with the VPMN SIM, and therefore may not be able to receive call-related and non-call related services on his HPMN MSISDN. In addition, when the roaming subscriber returns to the HPMN, he cannot use call-related and non call-related services on his VPMN MSISDN. Therefore, it is desirable to facilitate mobile communication corresponding to both the HPMN MSISDN and VPMN MSISDNs.
In one technique (such as that taught by the present inventor in PCT Application Number WO US04/004975 entitled, “Providing Multiple MSISDN Numbers in a Mobile Device with a Single IMSI”) to provide such a service to the roaming subscriber, the HPMN reserves a special range of HPMN IMSIs to provide the service. To subscribe for the service, the roaming subscriber needs to buy a special HPMN SIM card with an HPMN IMSI belonging to the special HPMN IMSI range. The HPMN assigns one or more VPMN MSISDNs to the subscriber upon subscription request and associates those VPMN MSISDNs with the HPMN MSISDN. The VPMN MSISDNs belong to a special range of VPMN MSISDNs reserved by each of the VPMNs. The roaming subscriber, when registered in the VPMNs, enjoys a local rate benefit on the VPMN MSISDNs and in addition, is able to receive call-related and non call-related services on the HPMN MSISDN. However, the roaming subscriber is able to use the services corresponding to his HPMN profile only, even when he is in the VPMN.
According to another technique (such as that taught by the present inventor in PCT Application Number WO WO US04/026410, entitled, “Signaling Gateway with Multiple IMSI with Multiple MSISDN (MIMM) Service in a Single SIM for Multiple Roaming Partners”) to provide the service, the roaming subscriber carries a special SIM card that contains an HPMN IMSI and multiple VPMN IMSIs, with corresponding HPMN MSISDN and VPMN MSISDNs, respectively. When the roaming subscriber registers in one of the VPMNs, a SIM Tool-Kit (STK) application residing in the SIM card automatically detects the current location of the roaming subscriber and selects a corresponding IMSI and MSISDN. The roaming subscriber then enjoys the local rate benefit in the VPMN.
However, in one or more of the aforementioned techniques, the HPMN must reserve the special range of HPMN IMSIs and the VPMNs must reserve the special range of the VPMN MSISDNs. In addition, the VPMNs need to configure corresponding network elements of the VPMNs to route signaling messages, such as Signaling Connection and Control Part (SCCP) messages, to a Signaling Gateway (SG) hosted either in the HPMN or in the VPMNs. In addition, the roaming subscriber is unable to use services corresponding to his local VPMN profile. Furthermore, the VPMNs have to perform special billing procedures for these special range of IMSIs.
According to another technique to provide the service that contains a distributed network of nodes for handling the service, the roaming subscriber carries a special SIM card that contains an HPMN IMSI and a SIM Tool-Kit (STK) application. When the roaming subscriber registers with a VPMN with the HPMN IMSI in a first registration attempt, the STK application informs a VPMN node about the roaming subscriber's location and an HPMN node. The VPMN node will then send a VPMN IMSI and a corresponding VPMN MSISDN to the roaming subscriber's SIM card. The STK will cause the handset to initiate a second registration attempt with the VPMN IMSI this time. Thereafter, the VPMN node provides information to the HPMN node about the roaming subscriber, i.e. the roaming subscriber's location, the VPMN IMSI, and the VPMN MSISDN. The roaming subscriber then enjoys the local rate benefit in the VPMN. The VPMN node and HPMN node also coordinate to handle call and SMS services, on either a HPMN number or a VPMN number. However, in this approach two registration attempts are required before the roaming subscriber is treated a local subscriber. Furthermore, a distributed network of nodes consisting of HPMN node and a node in each VPMN the subscriber visits, is also required.
In accordance with the foregoing, there is a need in the art for a cost-effective solution for facilitating mobile communication corresponding to the HPMN MSISDN and multiple VPMN MSISDNs of the roaming subscriber.